Japanese researchers say they have successfully copied fingerprint data from a digital picture of a person flashing a two-fingered "V" or peace sign, raising questions about the potential theft of such information.
"One can use it to assume another identity, such as accessing a smartphone or breaking and entering into a restricted area such as an apartment," Isao Echizen, a professor at Japan's National Institute of Informatics, told Reuters Television.
Flashing a two-finger peace sign is common among Japanese when posing for a photo.
Mr Echizen and fellow researcher Tateo Ogane reproduced an experiment on Friday in which they extracted Mr Echizen's fingerprints from a digital photograph taken at a distance of three metres.
The high-resolution photograph was taken with a 135mm lens mounted on a digital SLR camera.
Fingerprint scanners have found their way into mobile phones, laptops, external hard drives and electronic wallets as an alternative to authentication using passwords or personal identification numbers.
NTT Docomo, Japan's biggest mobile carrier, said it had not received any reports of misuse of fingerprint data on customers' devices.
"Fingerprint authentication is used for many purposes, including smartphones, and each manufacturer decides how the authentication process is maintained," spokesman Yasutaka Imai said.
"We'll continue to monitor the situation carefully".